The present invention relates to a flat knitting machine comprising front and back needle beds which are arranged to allow adjustment of a width of a needle bed gap therebetween.
In the flat knitting machine, at least a pair of front and back needle beds are arranged, with their heads confronting each other across a needle bed gap therebetween, and a large number of needles and sinkers are arrayed side by side on the respective needle beds. The dimension of the clearance or gap defined between front edges of the needle beds or sinkers confronting each other in front and back (hereinafter it is referred to as xe2x80x9cthe needle bed gapxe2x80x9d) is set in accordance with a needle gauge or a hook size of the flat knitting machine. Some of the flat knitting machines have the capability of adjusting the needle bed gap. The front edges of the needle beds are formed by a piano wire or a base plate of the needle bed itself. For example, the flat knitting machine of this type is constructed so that a plurality of knock-in holes for needle-bed-gap-adjusting knock-pins to be engaged in are bored in a base needle bed at both ends thereof, so that the mounting position of each needle bed on the base needle bed is changed by changing the positions of the knock pins to be inserted in the knock-in holes formed in the base needle beds in accordance with the size (L, M, S) of the needle hook of the needle set in the needle beds. This can allow the position changes of the front edges of the sinkers or the needle beds, to widen or narrow the needle bed gap, and as such enables texture of differences to be provided for a knitted fabric. For example, a knitted fabric of a 6-gauge texture or an 8-gauge texture can be produced by using a 7-gauge knitting machine.
Other flat knitting machines have a needle-bed retracting device which is constructed to retract the needle beds to their retracted positions from their advanced positions where ordinal knitting operations (knitting and loop transfer) are performed, in the course of the knitting of fabric, so that necessary knitting operations are performed at the retracted positions, and then restore the needle beds therefrom to their original advanced positions.
An example of this type of flat knitting machine is a flat knitting machine having a warp yarn insertion mechanism. In this flat knitting machine, while a knitted fabric is knitted by using a welt yarn, the front and back needle beds are kept at their advanced positions. On the other hand, when the knitted fabric is knitted by using a yarn feeder used to insert a warp yarn, i.e., a so-called a lace bar, the needle bed located below the lace bar is retracted downwardly to prevent interference with the lace bar which is swung when lapping operations are performed. For example, Japanese (Examined) Patent Publication No. Sho 51(1976)-42225 illustrates in FIG. 1 this type of flat knitting machine.
Another example is a so-called topping knitting machine which is constructed so that a knitted fabric of a border pattern or a like pattern is transferred from the needles on a needle bed to point needles on a transfer bar located below the needle bed. This topping knitting machine is also provided with a needle-bed retracting mechanism to prevent interference between a transfer member which is advanced from a position below the needle bed toward the needle bed gap and retracted therefrom and the needle bed. For example, Japanese Laid-open (Unexamined) Patent Publication No. Sho 46(1971)-973 illustrates in FIGS. 14 and 15 this type of flat knitting machine.
However, since the knitting machines cited above are all structured so that the entire heavy needle beds are moved toward and away from the needle bed gap in the advancing and retracting direction to change the dimension of the needle bed gap, a large force is required for the adjustment of the needle bed gap. The knitting machines disclosed by Japanese (Examined) Patent Publication No. Sho 51(1976)-42225 and Japanese Laid-open (unexamined) Patent Publication No. Sho 46(1971)-973 are provided with a large scale drive mechanism for providing the required force. On the other hand, in the knock-pin-and-knock-in-hole arrangement, since the positions of the knock pins to the knock-in holes formed in the base needle beds are changed at manual works in accordance with the size variations (L, M, S) of the needle hook of the needles set in the needle beds, no particular drive mechanism is needed, but considerable labor is needed for the position change, instead.
In the light of the problems mentioned above, the present invention has been made. It is an object of the present invention to provide a flat knitting machine that does not require such a large force as the prior art require for the adjustment of the needle bed gap.
Also, it is an object of the present invention to provide a flat knitting machine having the capability of adjusting a width of the needle bed gap between the needle beds in the course of the knitting of a knitted fabric.
The present invention provides a novel flat knitting machine comprising a number of needles arranged in needle grooves formed on needle beds in such a manner as to be freely advanced or retracted; sinkers, arranged between the needles, to work to form loops; and at least a pair of front and back needle beds having a front edge portion and arranged to confront each other across a needle bed gap, wherein the sinker and the front edge portion of the needle bed are both supported on the needle bed in such a manner as to be movable in an advancing and retracting direction of the needle and also control means is provided for controlling an advanced or retracted motion of both of the sinker and the front edge portion of the needle bed, to adjust a dimension of the needle bed gap between the front and back needle beds.
The control means controls the advanced or retracted motion of both of the sinkers and the front edge portion of the needle bed simultaneously.
According to this construction, since the sinker, arranged at the front end portion of the needle bed, to work to form a loop, and the front edge portion of the needle bed facing the needle bed gap between the front and back needle beds are both retractably supported on the needle bed to increase or decrease the width of the needle bed gap, the sinker and the front edge portion can be changed in position on the needle bed, as the need arises, to obtain a desired dimension of the needle bed gap.
In the flat knitting machine above, the sinkers are each supported to be freely advanced toward the needle bed gap or retracted therefrom in a sinker groove formed to extend from a front end of the needle bed toward a back side of the needle bed; the front edge portion of the needle bed is formed by a yarn retaining wire rod extending through insertion holes bored in the sinker in proximity of its front edge to be oriented orthogonal to an advancing-and-retracting direction of the needle and located below an advancing-and-retracting track of the needle; and a controlled portion provided in the sinker at a portion thereof extended along the back side of the needle bed is controllably advanced or retracted by the control means, to allow the advanced or retracted motion of the sinker and the yarn retaining wire rod, so as to adjust the dimension of the needle bed gap.
It is preferable that the respective sinkers are advanced or retracted by a slide member having a controlling portion simultaneously engageable with all of the controlled portions of the sinkers and extending in a width direction of the needle bed.
It is preferable that the controlled portion provided at the sinker is formed by an advance-and-retraction control butt projected out from the back side of the needle bed, and the control butt is engaged in a slotting cam provided in the slider member, to allow the advanced or retracted motion of the sinkers through the slotting cam.
According to this construction, the front edge of the needle bed, on which a loop is retained, is formed by a wire rod inserted in the insertion holes formed in the sinkers and supported by the sinkers, and the sinkers are each provided, at a rearward portion thereof extending along the back side of the needle bed, with the controlled portion engageable with the control means to controllably advance or retract the sinker. This can produce the result that when the controlled portion is advanced or retracted by the control means, not only the sinker but also the wire rod are advanced or retracted simultaneously to adjust the width of the needle bed gap. Also, since the controlled portion is disposed at the back side of the needle bed and is controlled by the control means, the configuration space can be easily ensured, as compared with the configuration wherein such a mechanism is arranged on the upper side of the needle bed.
Also, since the controlled portions of the sinkers arranged in parallel are all engaged in the controlling portion of the slide member which extends along a width direction of the needle bed and is engageable with all the controlled portions of the sinkers simultaneously, the dimension of the needle bed gap can be adjusted by simply operating the slide member to move back and force.
The butts of the sinkers engaged in the slotting cam are advanced and retracted through the slotting cam when the slide member is advanced or retracted.
The needle bed comprises a main body portion of the needle bed and a front end portion of the needle bed which is separated from and located forward of the main body portion of the needle bed and also is movable relative to the main body portion of the needle bed in the advancing-and-retracting direction of the needle and at which the sinker and the front edge portion of the needle bed are provided, and the front end portion of the needle bed is advanced or retracted by the control means, to adjust the dimension of the needle bed gap between the needle beds.
Also, the front end portion of the needle bed is retractably supported on the main body portion of the needle bed.
In this construction, the sinkers and the front end portion of the needle bed defining the front edge portions of the needle bed are formed to be separate from each other and are supported on the needle bed in such a manner as to be movable in the advancing and retracting direction of the needle, and the front end portion of the needle bed is advanced or retracted by the control means, to adjust the dimension of the needle bed gap between the front and back needle beds.
The front and back needle beds may each be provided with a mechanism for adjusting the dimension of the needle bed gap between the needle beds.
In this construction, since the sinkers and the front edge portion of the needle bed can be advanced or retracted separately on the front and back needle beds, the adjustable range of the dimension of the needle bed gap can be further increased. In addition, since the distance advanced or retracted by the front needle bed and the distance advanced or retracted by the back needle bed can be made equal to each other, the dimension of the needle bed gap can be changed finely in accordance with the changes in needle hook size (L, M, S) as well as knitting conditions, such as knitting material and knitting pattern, for knitting the knitted fabric.